Continuity mistake: When Xavier is surrounded by a group of mutants in his subconscious, if you look at Quicksilver you can see that the colorist made his shirt flesh-colored. You can tell he is supposed to be wearing a shirt because the lightning bolt design is still going across his torso.

Rogue rips off Donald Pierce's cybernetic left arm, but when he is first shown running away, his right arm is the one that is missing. When he catches up with Sebastian Shaw in the secret passageway, his left arm is back to being the one missing.